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Erik Andersen64371702000-03-04 22:23:27 +00001/* vi: set sw=4 ts=4: */
2/*
Rob Landley0b22c1c2006-03-14 02:40:51 +00003 * freeramdisk and fdflush implementations for busybox
Erik Andersen64371702000-03-04 22:23:27 +00004 *
5 * Copyright (C) 2000 and written by Emanuele Caratti <wiz@iol.it>
Eric Andersencb81e642003-07-14 21:21:08 +00006 * Adjusted a bit by Erik Andersen <andersen@codepoet.org>
Rob Landley0b22c1c2006-03-14 02:40:51 +00007 * Unified with fdflush by Tito Ragusa <farmatito@tiscali.it>
Erik Andersen64371702000-03-04 22:23:27 +00008 *
Denys Vlasenko0ef64bd2010-08-16 20:14:46 +02009 * Licensed under GPLv2, see file LICENSE in this source tree.
Erik Andersen64371702000-03-04 22:23:27 +000010 */
Denys Vlasenkodd898c92016-11-23 11:46:32 +010011//config:config FDFLUSH
Denys Vlasenko4eed2c62017-07-18 22:01:24 +020012//config: bool "fdflush (1.4 kb)"
Denys Vlasenkodd898c92016-11-23 11:46:32 +010013//config: default y
14//config: select PLATFORM_LINUX
15//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020016//config: fdflush is only needed when changing media on slightly-broken
17//config: removable media drives. It is used to make Linux believe that a
18//config: hardware disk-change switch has been actuated, which causes Linux to
19//config: forget anything it has cached from the previous media. If you have
20//config: such a slightly-broken drive, you will need to run fdflush every time
21//config: you change a disk. Most people have working hardware and can safely
22//config: leave this disabled.
Denys Vlasenkodd898c92016-11-23 11:46:32 +010023//config:
24//config:config FREERAMDISK
Denys Vlasenko4eed2c62017-07-18 22:01:24 +020025//config: bool "freeramdisk (1.4 kb)"
Denys Vlasenkodd898c92016-11-23 11:46:32 +010026//config: default y
27//config: select PLATFORM_LINUX
28//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020029//config: Linux allows you to create ramdisks. This utility allows you to
30//config: delete them and completely free all memory that was used for the
31//config: ramdisk. For example, if you boot Linux into a ramdisk and later
32//config: pivot_root, you may want to free the memory that is allocated to the
33//config: ramdisk. If you have no use for freeing memory from a ramdisk, leave
34//config: this disabled.
Denys Vlasenkodd898c92016-11-23 11:46:32 +010035
Denys Vlasenko205d48e2017-01-29 14:57:33 +010036// APPLET_ODDNAME:name main location suid_type help
Denys Vlasenkodd898c92016-11-23 11:46:32 +010037//applet:IF_FDFLUSH(APPLET_ODDNAME(fdflush, freeramdisk, BB_DIR_BIN, BB_SUID_DROP, fdflush))
38//applet:IF_FREERAMDISK(APPLET(freeramdisk, BB_DIR_SBIN, BB_SUID_DROP))
39
40//kbuild:lib-$(CONFIG_FDFLUSH) += freeramdisk.o
41//kbuild:lib-$(CONFIG_FREERAMDISK) += freeramdisk.o
Pere Orga5bc8c002011-04-11 03:29:49 +020042
43//usage:#define freeramdisk_trivial_usage
44//usage: "DEVICE"
45//usage:#define freeramdisk_full_usage "\n\n"
46//usage: "Free all memory used by the specified ramdisk"
47//usage:
48//usage:#define freeramdisk_example_usage
49//usage: "$ freeramdisk /dev/ram2\n"
50//usage:
51//usage:#define fdflush_trivial_usage
52//usage: "DEVICE"
53//usage:#define fdflush_full_usage "\n\n"
54//usage: "Force floppy disk drive to detect disk change"
55
Denys Vlasenkoda49f582009-07-08 02:58:38 +020056#include <sys/mount.h>
Denis Vlasenkob6adbf12007-05-26 19:00:18 +000057#include "libbb.h"
Erik Andersen64371702000-03-04 22:23:27 +000058
Bernhard Reutner-Fischer2523da22006-03-18 23:02:45 +000059/* From <linux/fd.h> */
60#define FDFLUSH _IO(2,0x4b)
61
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +000062int freeramdisk_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denys Vlasenkoe992bae2009-11-28 15:18:53 +010063int freeramdisk_main(int argc UNUSED_PARAM, char **argv)
Erik Andersen64371702000-03-04 22:23:27 +000064{
Glenn L McGrath8c6887c2003-05-08 13:09:28 +000065 int fd;
Erik Andersen64371702000-03-04 22:23:27 +000066
Denys Vlasenkoe992bae2009-11-28 15:18:53 +010067 fd = xopen(single_argv(argv), O_RDWR);
Eric Andersenc7bda1c2004-03-15 08:29:22 +000068
Rob Landley0b22c1c2006-03-14 02:40:51 +000069 // Act like freeramdisk, fdflush, or both depending on configuration.
Denys Vlasenko74c05f52017-08-04 17:36:16 +020070 ioctl_or_perror_and_die(fd,
71 ((ENABLE_FREERAMDISK && applet_name[1] == 'r') || !ENABLE_FDFLUSH)
72 ? BLKFLSBUF
73 : FDFLUSH,
74 NULL, "%s", argv[1]
75 );
Rob Landley658d2cf2005-09-08 03:11:58 +000076
77 if (ENABLE_FEATURE_CLEAN_UP) close(fd);
78
Matt Kraai3e856ce2000-12-01 02:55:13 +000079 return EXIT_SUCCESS;
Erik Andersen64371702000-03-04 22:23:27 +000080}